- fix segment limit mis-calculation for GCODE_SEL, GDATA_SEL, GPRIV_SEL,
LUCODE_SEL and LUDATA_SEL.
- move `loader(8) metadata' related printf() after cninit().
- use atop macro (address to pages) for segment limit calculation
instead of i386_btop macro (bytes to pages).
- fix style bugs for the declarations of ints.
Reviewed by: bde, msmith (and arch & audit ML)